Means for the production or reproduction of sound or like vibrations



s. G. BROWN I MEANS FOR THE PRODUCTION OR REPRODUCTION OF SOUND OR LIKE VIBRATIONS April 12, 1927.

Filed Sept. 4, 1923 3 Sheets-Sheet 1 A til 12 192 v p 7 s. 0. BROWN.

MEANS FOR THE PRODUCTION OR REPRODUCTMN OF soum) 0R LIKE VI-BRATIONS Filed Sept. 4. 1 923 i s Sheets-Sheet 2 510% G tors: drawn:

April 12, wzz 1,624,823

S. G. BROWN MEANS FOR THE PRODUCTION OR REPRODUCXION OF SOUND OR LIKE VIBRATIONS Filed se tfl 4. 1925 s Sheets-Sheet 3 Patented Apr. 12,1927. 7

UNITED STATES. PATENT. GREE E SIDNEY GEORGE BROW or NORTH ACTON, Enema-Ni).

MEANS iron. a r-1n rnonuorroiv on REPRODUCTION or soimn on nIKE vxiana'rrolvs.

Application filed. September 4, 1923, Serial No. 660,748, and in Great Britain October 12, 1922.

i This invention relates to improved means by which' sound; or mechanical vibrations may be produced I, or reproduced by the method in which a member rubbing upon a relatively moving surface is set into vibration by the alternate gripping and release of the contacting surfaces.

I have found that if one of the surfaces is of polished or glass-like nature it is possible to reproduce sounds such as speech sounds with great ,clearness and considerable intensity by controlling in a vibratory mannor the rubbing member, and according to 7 one feature ofthis invention I employ with a surface of this type a rubbing member which lies closely upon the surface over a substantial area and is maintained by pres sure against'th'e surface, the pressure vary ing by vibratory action under the control of the source of primary vibrations, the

said rubbing member being connected to a sound emittingor transmitting member so as to set up secondary vibrations, by the alternate pull and release of the rubbing member, which are of amplitude and period depending upon the amplitude and period of the controlling vibrations. The iubbing surface is carefully fitted to lie on the relatively moving surfacef and is preferably .ground tov shape. The moving surface, which may be of polished glass 'or hard metal such as steel, is usually in the form of rotating disc driven at a moderate speed by clockwork or other mechanism, ora rotatiiig drum similarly driven oravco-ne,"and

the polished surface may be coated with a very thin film of a; slightly tacky material I which is so thin that-it does not give sub- 'ploying a rotating drum or cylinder.

stantial' adhesion, but makes the clinging action of the rubbingjmeinber more conble steel backed cork strip lapping round a portion of the circumference arrdpressed towards its, free end "by the controlling source,

of vibrations. I y y The controlling primary vibrations may 'be derived from a telephone receiver, a

voice; operated diaphragm, a gramo plioneneedle sorothervibratory member and the transmission to the rubbing member' is preferably efi'ectedby a small pin or stud, which 1 may be; flexible and may be arranged to have fully with reference to showninflF-igures 1,2 and 3.

telephone receiver orother source of primary vibrations, which is arranged upon a rocking support provided with a balancing weight by'which the. pressureon the rubbing member may be regulated; .or the telephonemay be separately mounted on a rockingsupport and the diaphragm for producing the secondary vibrations nounted on a rigid or independently 'displa'ceable support carrying a sound horn, i

In order that the said invention may be clearly understood and readily carried into efliect,*the same will now be described more a g the accompanying drawings, in which I Figure 1 is a-plan and F igure 2 a side ele vation' of one form. of apparatus embodying this invention. I

Figure 3 is a detail view showing a portion of the apparatus .paitly in plan and partly in section. p I

Figure 4 is a detail View of a. rubbing member in the form of a flat pad as used in the apparatus of Figures 1, 2 and 3. I

F igures 5 and 6 are, respectively, a plan and elevation of a modified construction of so I apparatus of similar general type to that Figures 7 and 8 area plannnd an elevation show ng a further modification of which Figure 9 is a detail view.

Figure 10 illustratesa modification ein- Referring' to the construction shown in Figures 1 to 4, A is. the supporting plate or.

base of the instrument, which may form the top of a box containing clockwork mecha nism of'thetype employed in gramophones. Bis the rotating disc which is driven at a steady 'moderate rate,- consider-ably slower than the usual gi'aniophone disc, drive, the disc B having a very smooth orpolished upper surface. It is mounted upon the rotating carrier 79 driven through the vertical spindle 121. C is the. rubbing member in the form of a small flat disc, the rubbing surface of which is formed bytlre thin face disc c, which may be of corlnthis material having been found to give good results, the face iio disc being cemented on the thin steel plate or disc 0 D is the flexible connection from the disc C to the sound emitting or transmitting member shown in the form of a conical diaphragm E, the flexible connection com prising a. doubled filament or thread firmly secured on the back of the disc C and attached at one end to the diaphragm E through the hook e and at the other end attached to the spring d carried by the adjustable stationary member (P. The connection D and disc C can therefore be immediately detached and fitted in place as required. The direct connection to a diaphragm is not necessary and connectlon may be made through a lever as in a gramophone sound box.

F is a telephone receiver which may, how ever, be replaced by any other source of con trolling oscillations. This receiver is mounted over the disc B towards one side so that its cent-re is over the centre of the rubbing disc C, a pin attached to the vibrating member of the receiver, such as a diaphragm or reed, resting upon the back of the disc C. The receiver is mounted on the rocking frame Gr supported by the pivot pins g carried in the standards a of the base A, the frame being provided with the adjustable balancing weight g on the arm y so that the pressure exerted by the pin on the back of the disc O is adjusted to the required amount.

H is a sound horn of ordinary gramophone type, the smaller end of the horn extending to the back of the face plate 9 of the frame G, this plate having a central. opening in which the conical diaphragm E is secured around its edge by means of a connecting member g which extends into the smaller end of the horn H. As the axis of adjustment of the frame G passes through the smaller end of the horn close to its extremity the frame can be raised or turned back to raise the receiver from the rotating disc without interfering with the horn, the inner end of the connecting member y" forming a box which maintains the inner end of the horn closed, but provides a sound aperture leading into the horn from the space at the back of the diaphragm E.

As already described, the rotating disc B may have a very fine film of friction producing material, such as resin, as thishas been found to give a better result than the untreated polished surface and enables the gripping surface to be renewed at any time so that a constant condition can be ensured. The pin f which bears on the back of the pad or disc C is preferably of resilient material to allow of the slight lateral vibratory movements without putting undue stressees on the controlling receiver or equivalent con trolling instrument.

can be given any desired backward or 1=0'1--' ward slope, If the slope is in the direction of motion of the disc B the tendency of the pin is to yield to the pull on the pad C due to the rotation, while if the slope is in the opposite direction the tendency is to increasethe grip. The amplification may therefore be carried by adjustment of the angle. The lug of the carrier is secured in adjusted position by the set screw 7' In the construction of Figures 5 and 6 the horn H serves as part of the pivotal support of the frame G, the box member g behind the diaphragm being of elbow form and projecting into the end of the horn, which is provided with a small cross bearing piece [a receiving a pivot ping fixed at the end of the elbow piece g The pivot is in line with the opposite pivot pin g. The balance weight g is shown mounted on two arms pivoted at above the axis of the elbow piece g so that when the frame G is turned up to lift the receiver clear of the rotating disc the weight will hold it up, out of the way.

In the modification shown in Figures 7,

8 and 9 the mounting of the receiver F is independent of the horn mounting, the horn H being carried by the elbow g mounted on a fixed support formed by a wall of the enclosing box G which carries the diaphragm inside the cover The receiver F is mounted in the ring carrier J carried by the support pivoted at in the fixed bracket a mounted on the base A which forms the top of the box AH The carrier J is itself pivoted at 7' in the support y" with a limited movement allowing it to be turned back with the receiver F when the instrument is to be thrown out of action. The counterbalancing weight j on an arm 7' of the pivoted support 7' determines the pressure exerted by the pin f of the receiver F on the back of the pad C. The receiver may be arranged for angular adjustment of the pin f as in the previously described an rangement.

I Figure 8 shows a simple means for stopping the motor driven disc B, in the form of a spring brake arm K adapted to bear on the edge of the supporting disc 6, the arm being carried on the underside of the base The modified construction of Figures 5 A and passing through an aperture in the base. The brake arm is operated by the already described may be applied to apparatus in which the moving member is of other form and in Figure 10 a diagrammatic representation of a rotating drum device is shown. B is the rotating'drum or cylinder above-Which is placedthe receiver F or equivalent device, such as a diaphragm, with pin f resting on the pad C The latter. is mounted upon a flexible member in the form of a strap D lapping around a substantial part of the cylinder and of any suitable gripping material. A cork strap with thin steel backing has been found suitable. One end of the strap is connected to the diaphragm E While the other may be free or attached to a spring as in the case of the flexible members shown in the other figures The large surface of grip enables considerable magnification to be obtained Without much pressure on the pad. grip may be increased by grooving the drum and making the gripping member of form corresponding to the groove so that it lies closely against the grooved surface.

\Vhat I claim and desire to secure by Letters Patent of the United States is 1. In phonic apparatus the combination comprising a movable body having a smooth surface, a rubbing member contactable with said surface, primary Vibrating means, a single instrumentality connecting said primary vibrating means to said rubbing member, and secondary vibrating means-connected to said rubbing member for magnifying said primary vibrations, as set forth.

2. In phonic apparatus the combination comprising a movable body having a smooth surface, a rubbing membercontactable with said surface, primary vibrating means, a pin-like member of resilient material (3( 1'l nected at one end to said primary vibrating means and at the other end to said rubbing member, and secondary vibrating means connected-to said rubbing member for mag- If desired the nifying said primary vibrations, as set forth.- I

3. In phonic apparatus the combination comprising a rotatable body having a polislied surface, a rubbing member contactable with said surface, primary vibrating means, means directly connecting said priconnecting means With respect to said rubbing member While maintaining their angle constant With respect to said primary vibrating means, and secondary vibrating means connected to said rubbing member I 1 mary vibrating means to said rubbing member, means for altering the angle of said forLm-agnifying said primaryvibrations, as

set forth.

4. In phonic apparatus, the combination comprising a movable body having a smooth surface, friction-producing material applied to said smooth surface in a thin film, a rubbing member contactable with said film, primary vibrating means, means connecting said primary vibrating means to said rubbing member for varying the pressure thereof upon said film, and secondary vibrating means connected to said rubbing member for magnifying said primary vibrations, as set forth. r

5. In phonic apparatus, the combination comprising a rotatable body of glass having a smooth surface, friction-producing material applied to said surface in a thin film, a rubbing member 'contactable with said film, primary vibrating means, means connecting said primary vibrating means to said rubbing member for varying the pres sure thereof upon said film and secondary vibrating means connectedfto said rubbing member for magnifying said primary vibrations, as setfortli.

6. In phonic apparatus the combination comprising a rotatable body of glass having a smooth surface,-resin applied to said surface in a thin him, a rubbingmember contactable With said film, primary vibrating i'neaiis, means connecting said primary vibrating means .to said rubbing member for varying the pressure thereof upon said film and secondary vib 'ating means connected to said rubbing member for magnifyingsaid primary vibrations, as set fortl SIDNEY GEORGE BROWN. 1 

